Breast cancer is one of the most frequent tumors in women, and BRCA1 and BRCA2 genes play a major role in the hereditary susceptibility for this disease. Until the age of 70 women carrying a mutation ...in BRCA1 or BRCA2 gene have a 45-85% probability of developing breast cancer, and 11-62% probability of developing ovarian cancer. Mutation carrier's tumors contain nonfunctional BRCA1 or BRCA2 genes, which in healthy cells are involved in DNA repair. These tumors show an increased sensitivity to DNA damaging chemical agents and to PARP (poly(adenosine diphosphate-ribose) polymerase1) inhibitors. New targeted therapies already in use are directed toward tumors of mutation carriers. Successful treatment is most likely to be achieved through cooperation of a pathologist, oncologist and a genetic laboratory performing BRCA genes mutation screening.
Gorlin syndrome is a rare autosomal-dominant disorder characterized by a wide range of developmental abnormalities and various tumors. The syndrome is caused by mutations in PTCH1, a tumor suppressor ...gene located at 9q22.32. We describe a Gorlin syndrome case with typical features of the syndrome and no mutations in PTCH1, but with a large deletion of the 9q22 region that has rarely been described.
To fully characterize the large deletion in the patient.
In order to map the size and position of the deletion, we developed quantitative multiplex fluorescent PCR with polymorphic markers surrounding the PTCH1 gene, followed by long-range PCR and sequencing.
The deleted segment of 4.5 Mb in the 9q22.32-q22.33 region was determined, and included the entire PTCH1, its promoter and 22 OMIM genes.
We suggest that screening for large deletions should be included in standard mutation screening for Gorlin syndrome patients.
Loss of heterozygosity (LOH) of tumor suppressor genes is a frequent event in tumorigenesis. LOH is most often analyzed by microsatellite typing, but here we offer a fast and efficient method for ...simultaneous SNP genotyping and mutation scanning, which can also be used for LOH detection. High resolution melting (HRM) provides simple variant detection, and can be adopted for a wide range of applications. When a melting profile for a specific SNP is determined, the screening can be done without the need for sequencing, and only the melting profiles differing from the established melting profiles should be sequenced. LOH of PTCH1 gene is often found in a series of different tumors, for example basal cell carcinoma (BCC) and ovarian carcinoma (OC). In this study LOH was detected in 50 % of BCC and 27.27 % of OC, and the detection rates of microsatellite typing and HRM were comparable. Both methods depended only on the heterozygosity of the loci analyzed, but HRM offers an additional advantage of detection of all sequence variants in the gene of interest.
Twomainmechanisms for eukaryotic initiation of protein synthesis have been described – the canonical cap-dependent and the alternative cap-independent. They mainly differ in their requirement for ...7-methylguanosine cap at 5’ end of mRNAmolecules to initiate translation. In cap-independent translation initiation, an element within 5’ untranslated region (5’UTR) ofmRNA, defined internal
ribosome entry site (IRES), recruits 40S ribosomal subunit directly or
close to the start codon without the need for the 5’ cap.
Some cellular mRNAs – including those encoding for a number of growth factors, oncogenes, receptors, survival proteins, transcription and translation factors – contain IRES elements within their 5’ UTR what may allow them to be translated under different physiological or stress conditions (e.g., amino acid starvation, apoptosis, growth arrest, heat shock,mitosis, radiation) when global cap-dependent protein synthesis is suppressed. IRES-dependent translationmay
escape the control of checkpoints present in cap-dependent regulation causing improper protein synthesis that can lead to cell apoptosis or disease. A growing number of cancer-related genes have been reported whose translation initiation depends on the presence of IRES element in their mRNA. These findings make
the quest for discovering and testing new putative cellular IRESes even more meaningful. A deeper understanding of the role of IRES-dependent translation initiation in cancer etiology could ultimately give us a novel targets for cancer therapy.
In the Milan area (Northern Italy), we identified a family characterized by a high prevalence of ovarian and breast cancer cases (5 out of 6 subjects, over 3 generations), and a predominant ...prevalence of ovarian lesions (4 out of 5 patients). Analysis of BRCA1 and BRCA2 genes allowed the identification of the missense c.190T>C mutation in codon 64 (Cys64Arg) of BRCA1. The aims of the present investigation were to characterize the functional implications of the c.190T>C mutation at the molecular level, and to search whether additional polymorphisms might be linked to the peculiar phenotypic features observed in the Italian pedigree. Molecular modelling studies suggested that substitution of the cysteine 64 with an arginine likely disrupts the architecture of the BRCA1 RING finger domain, responsible for the interaction with BARD1, essential for the tumor-suppressor activity of the BRCA1-BARD1 complex. By splicing site information analysis, exonic splicing enhancer site characterization, and analysis of transcript fragment length and sequence, we showed that the c.190T>C mutation was able to modulate the splicing of exon 5 in a fashion opposite to the c.190T>G transversion, responsible for the functionally-related Cys64Gly amino acid substitution. Genotyping of BRCA1 and BRCA2 in the Italian family revealed the presence of two significant polymorphisms: the cancer-associated c.2612C>T SNP in BRCA1, and the c.-26G>A SNP in the BRCA2 gene, acting as an ovarian cancer risk modifier in carriers of deleterious BRCA1 mutations. Analysis of these SNPs in a genotypically-unrelated Polish family, characterized by prevalent breast neoplasms in carriers of the c.190T>C mutation, revealed a genetic profile consistent with the hypothetic role of both polymorphisms.
: We compared the expression of target genes of Hedgehog/Patched signaling in ovarian fibromas and ovarian dermoids. We noted that high levels of SHH appear almost regularly, especially in dermoids, ...usually accompanied by increased expression of SMO. GLI overexpression does not coincide with that of PTCH. Loss of heterozygosity findings in the PTCH locus and increased expression of several genes in the pathway strongly suggest that the pathway is involved in both ovarian fibroma and dermoids.
Studies on the variability of human papillomavirus (HPV) type 16 are based mostly on DNA sequencing of the viral oncogenes E6 and E7. In order to simplify variant identification, high resolution ...melting (HRM) analysis, which has been shown to distinguish amplicons differing in a single nucleotide, was employed.
Optimised HRM analysis was applied to 255 anogenital samples positive for HPV 16. The E6/E7 region of the HPV 16 genome was amplified using nested PCR with subsequent melting of the amplicons. Samples giving ambiguous melting profiles were melted again in the presence of reference HPV 16 DNA to define and confirm the novel melting profiles.
Out of 219 samples of Croatian origin, 65 reference variants, 119 E6-360G variants and 35 novel melting profiles were found. Samples containing unusual profiles were sequenced for identification. In addition, a subset of samples with two common variants, 23 reference and 34 E6-350G variants, was also sequenced to confirm the findings of high resolution melting. Concordance between the melting analysis and sequencing was 93.9%, while HRM sensitivity and specificity were 92.9% and 94.7%, respectively.
This study showed that HRM analysis can be useful for the identification of HPV 16 variants. The HRM method will be useful in low resource settings as it saves considerable time and resources compared to sequencing.
Transition from malignant schwannoma to malignant triton tumor is analyzed in a case report on a patient with recurring cancers and suspected familial predisposition. It is hypothesized that ...rhabdomyoblastic differentiation, which distinguishes triton from schwannoma, might be attributable to Hedgehog-Patched pathway malfunctioning. Loss of one Patched gene allele was found in the tissue of advanced triton, but the retained allele had no exon or promoter mutations. Protein levels at early cancer stages indicated possible Patched response to the pathway activation in the first occurrence of triton tumor. Later, in the recurring triton, Patched expression was several times lower than in the control tissue, suggesting that haploinsufficiency was aided by silencing of the remaining allele, although its promoter was not hypermethylated. These findings may justify further investigation of the Hedgehog-Patched pathway role in triton malignancies, especially because of the recent research on the therapeutical potential of the pathway.
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